1. Lecture 6
People and peoples in history
and pre-history
Malthusian population theory, Celts
and Romans 1200BC to 900AD
Reading, Fagan 2004 Chapter 10

2. Malthus’ Population Theory
http://www.hort.purdue.edu/newcrop/tropical/lecture_14/lec_14.html

3. • Thomas Malthus: English scholar 1776-1834
• Proposed that “The power of population is indefinitely
greater than the power in the earth to produce
subsistence for man". ie. population growth is
geometric eg. 2,4,8 etc whereas resources
growth is arithmetic eg. 1,2,3 etc
• That the increase of population is necessarily
limited by the means of subsistence
• That population does invariably increase when
the means of subsistence increase
• Society relies on human misery to limit
population growth eg. famine, disease, war,
natural disaster

4. Neo-Malthusian theory
• World population
currently in state
of rapid increase
• If plot population
on log. scale,
three distinct
phases apparent

5. Neo-Malthusian Theory
• Two approaches – ’alarmists’ (population
explosion, mass starvation) and ‘technocrats’
(science and technology will find a way)
• Malthus did not foresee tremendous growth of
food with modern agriculture
• Also the ‘demographic transition’ –
accompanying economic development and
urbanisation – death rates fall, followed by
declining birth rates – developed countries first

6. Demographic transition
• In 1875 birth rate
high 40 per
thousand population
(4%)
• By 1975 only 1.5-2%

7. World population growth
• Current world popn.
6 billion
• Expected 12 billion
by 2100
• World food
production has kept
up but there is
disequilibrium
between countries

8. World Population Growth, 1990–
2100
Population (billions) Increase (%)
Countries 1990 2025 2100 1990–2100
Developing 4.08 7.07 10.20 250
Developed 1.21 1.40 1.50 24
World Total 5.30 8.47 11.70
• Future- population pressures will vary with
location low birth rates in Europe, America,
China stabilising, India increasing rapidly,
Africa unstable due to Aids, political
instability, warfare
• Climate is a wild card

9. Climate and Human history
• Palaeolithic period throughout Pleistocene glacial
period, from 2.5m ya to end of last glacial 10k ya-
alternating cold and warm phases
• Prehistoric period of human history
• Earliest hominids Autralopithicenes 2.6m ya- used
fire and stone tools
Many great mammals such as woolly mammoth, woolly rhinoceros and cave lions
inhabited places like Siberia during Pleistocene

10. Human ‘ages’
• Palaeolithic
• Mesolithic
• Neolithic
• Stone age 200k BC
• Bronze age 3-1000 BC
• Iron age 1000 BC

11. Humans in Pleistocene
• Palaeolothic distinguished by development of
stone tools – also used wood,bone, leather and
fibres- beginning of human control of environment
• Homo-sapiens evolved from earlier primates
200,000 y ago
• Human society grouped in small bands, gathered
plants and hunted wild animals
Palaeoindians hunting a
Glyptodon: driven to
extinction after humans
arrived in S. America
Artist’s impression of
a human house based
on evidence found in
Nice, and dated to
Lower Palaeolithic
400ka BP

12. Climate and Peoples in Europe
during Neolithic period
Neolithic House from Orkney Islands
(N. of Scotland)
Neolithic House from Jura
area of N. Italy

13. Neolithic Climatic trends
Neolithic period (10ky BC) – beginning of
human settlement – due to Farmers
adapting to cooling, by growing millet
(can stand short growing season and
drought, can store well)
• Millet provided grain for bread and
porridge, and fermented for beer
• Also grew beans – fast growing in cool
climate
• A gradual cooling over Europe since
3500BC- climate increasingly continental
Lima beans

14. Temperatures of last 11,000 years
Add map on p.195- climatic zones
Last 3,000 years

15. Neolithic Climatic fluctuations
• Volcanic eruptions throughout Neolithic
age from Icelandic volcanoes brought
cooling episodes lasting up to 5 years
eg.Hekla eruption in 1159BC
• Subsistence farmers only enough grain to
get through one band harvest and plant
for the next - cold summers brought winter
famine as well as the ‘cutting cold and
dreaded darkness’

16. Meet Otzi
• The Ice Man – frozen
corpse from 3100BC
found high in Alps
• “Harris lines’ on bones
resulting from
malnutrution at ages 9,
15 and 16
His quiver held 14 arrows

17. Bronze and Iron ages:
Europe divided by climate
• Celts (Gauls) lived N. of Alps often raided
settlements to S. eg. 390BC raid on Rome
• Their homeland cold, wet, difficult to farm:
subsistence agriculture dependent on summer
rain: Greenland high pressure in winter many
deaths
• Mediterranean zone mild- wet winter, dry hot
summer
• Boundary b/w N and S Europe shifted N and S,
past 3000 years (Bronze age though Iron Age)

18. Bronze age Europe

19. Culture of the northern Celts
• Small round houses in hamlets or villages
with farmland among the wooded landscape
• Society dominated by local chiefs: life revolved
around the field, household and village workshop
• Cultivated wheat and barley (wheat intolerant of
heavy rain and cold summers), turnips, potatoes
• Use of amber and bronze for currency

20. Shaugh Moor, Dartmoor, UK
Bronze age field boundaries marked by low stone walls

21. Bronze age Subsistence farming
• Even in good years, threat of winter famine
present
• Only ancient ties of kinship, social reciprocity, use
of wild plant food and game ensured survival
• In good years agric prod increases, populations
increase, additional woodland cleared and grazing
on marginal uplands eg. Shaugh Moor
• Invisible equation b/w popn/good harvests/land
carrying capacity
• Almost always ppl farmed close to limit and
beyond
• Many hungry winters, and people died
• Hunger and malnutrition a fact of bronze age life

22. Iron age culture 1000BC
• Used iron tools and ploughs farmed landscape
• Much of what Romans called “Gaul” (France) and
southern Britain came under cultivation
• Julius Caesar visiting Britain in 55 BC noted popn. was
‘exceedingly large, the ground thickly studded with
homesteads”
• Iron also enabled better weapons – coupled with
crowding of the landscape – many local wars
• Life revolved around farming, war and cattle herding
• Subsistence agric - In drought years they fall back on
game and edible plants or try to develop more land
• By 400BC no more land, if cannot move, wars erupt
• Resulted in the great Celtic migrations of 4thCentury BC
• Ferocious Celtic warriors went south- conquered Rome
in 390BC
• Whenever climate changed to warmer- ecotone b/w
Mediterranean and continental moved north

23. Tragedy of the Commons

24. Tragedy of the commons
• what can happen in groups when
individuals act in their own best self
interests and ignore what’s best for the
whole group
• group of herdsmen share a communal
pasture, and all want their own cattle to
get as much grass as possible
• brings unintentional tragedy -destruction of
the common grazing area
• Other examples – world fisheries, waste
disposal - NIMBY

25. Tragedy of Commons: solutions
• Provide more information to avoid
uncertainty
• Reinforce social identity and sense of
community
• Need to trust governing bodies
• Incentives for reducing over-use/penalties
• People have fundamental need to
understand environment
Van Vugt, M. (2009). Averting the tragedy of the commons: Using social psychological science to protect
the environment. Current Directions in Psychological Science, 18(3), 169-173.
http://psychcentral.com/blog/archives/2009/07/29/the-tragedy-of-the-commons/

26. Please read
Lee, H.F. and Zhang, D.D. 2012. “A tale of two population
crises in recent Chinese History”, Climatic Change
DOI 10.1007/s10584-012-0490-9, before next lecture
Pay particular attention to:
social coping mechanisms
relationship between climate and social conflict

27. A tale of two population crises in
recent Chinese History
• Now we skip 4 centuries to 17thC Ming Dynasty
• Research on impacts of recent climate change on
population by HKU, using over 100 data sources
• Focus on 2 short periods of popn collapse 1626-
46 and 1852-70
• Challenged conventional Malthusian theory of
cycles of population catastrophe and overshooting
of resources
• Much more data available than previous epochs,
so premises for theories more sound
• Provides insight into how Malthusian mechanisms
actually work and many parameters involved

28. Initial hypotheses
• In an agricultural economy with low level of technology,
temperature change will affect population growth by
reducing agric. prodn.
• In pre-industrial era, technological innovation cannot
aleviate popn. pressure (resulting from land carrying
capacity vs. popn growth) and in past Chinese popn.
already reached demographic saturation repeatedly (ie.
state of near-starvation and misery) (but not population
collapse due to social buffering mechanisms)
• When there is long-term climate change, popn collapse is
caused by shrinkage of land carrying capacity beyond
social coping mechanisms famine, epidemics, wars
• Cold periods often accompanied with variability – floods,
droughts. Tendency to cultivate marginal lands in periods
of popn. pressure increases susceptibility to floods and
drought

29. Initial Hypotheses
• Weakened agric production of the state creates
internal conflicts, reducing resistance to external
invasion: war and invasion often go together
• Mass migration driven by famine/war facilitiates
spread of disease
• Mass migration causes violent conflict b/w
nomads and settled farmers over land and food
• Because mortality factors interlinked, popn.
collapse occurred, then followed by reduced
popn. pressure, and decrease of mortality factors
• Sequence followed by renewed popn. growth-
another cycle

30. Population growth in agrarian
China
Arrows mean Change in X means change in Y – positive or negative

32. Questions to ask
• Starting from the relationship between
climate change and population pressure in
prehistoric China, do you see any parallels
in the modern world?
• Can lessons learnt from the past inform
our response to modern day climate
change?